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BUG: KCSAN: data-race in rwsem_down_write_slowpath / rwsem_down_write_slowpath

write to 0xffffc9000351bb58 of 1 bytes by task 16860 on cpu 0:
 rwsem_try_write_lock kernel/locking/rwsem.c:653 [inline]
 rwsem_down_write_slowpath+0x3c9/0xa90 kernel/locking/rwsem.c:1159
 __down_write_common kernel/locking/rwsem.c:1317 [inline]
 __down_write kernel/locking/rwsem.c:1326 [inline]
 down_write+0xab/0xc0 kernel/locking/rwsem.c:1591
 kernfs_remove_by_name_ns+0x5c/0xf0 fs/kernfs/dir.c:1717
 kernfs_remove_by_name include/linux/kernfs.h:633 [inline]
 sysfs_unmerge_group+0x80/0xb0 fs/sysfs/group.c:408
 dpm_sysfs_remove+0x4c/0x90 drivers/base/power/sysfs.c:830
 device_del+0x13d/0x790 drivers/base/core.c:3855
 netdev_unregister_kobject+0x24d/0x270 net/core/net-sysfs.c:2329
 unregister_netdevice_many_notify+0x1346/0x1710 net/core/dev.c:12466
 unregister_netdevice_many net/core/dev.c:12494 [inline]
 unregister_netdevice_queue+0x1cd/0x200 net/core/dev.c:12308
 unregister_netdevice include/linux/netdevice.h:3409 [inline]
 __tun_detach+0x82c/0xb30 drivers/net/tun.c:621
 tun_detach drivers/net/tun.c:637 [inline]
 tun_chr_close+0x5a/0x100 drivers/net/tun.c:3436
 __fput+0x29b/0x650 fs/file_table.c:469
 ____fput+0x1c/0x30 fs/file_table.c:497
 task_work_run+0x130/0x1a0 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x4ae/0x1600 kernel/exit.c:976
 do_group_exit+0xfe/0x140 kernel/exit.c:1118
 get_signal+0xe54/0xf60 kernel/signal.c:3034
 arch_do_signal_or_restart+0x96/0x450 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:98 [inline]
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:270 [inline]
 irqentry_exit_to_user_mode include/linux/irq-entry-common.h:339 [inline]
 irqentry_exit+0xf7/0x520 kernel/entry/common.c:219
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618

read to 0xffffc9000351bb58 of 1 bytes by task 4579 on cpu 1:
 rwsem_down_write_slowpath+0x43d/0xa90 kernel/locking/rwsem.c:1177
 __down_write_common kernel/locking/rwsem.c:1317 [inline]
 __down_write kernel/locking/rwsem.c:1326 [inline]
 down_write+0xab/0xc0 kernel/locking/rwsem.c:1591
 kernfs_remove_by_name_ns+0x5c/0xf0 fs/kernfs/dir.c:1717
 kernfs_remove_by_name include/linux/kernfs.h:633 [inline]
 remove_files fs/sysfs/group.c:28 [inline]
 sysfs_remove_group+0xa5/0x170 fs/sysfs/group.c:328
 sysfs_remove_groups+0x3a/0x80 fs/sysfs/group.c:352
 destroy_port drivers/infiniband/core/sysfs.c:1233 [inline]
 ib_free_port_attrs+0x173/0x260 drivers/infiniband/core/sysfs.c:1363
 remove_one_compat_dev drivers/infiniband/core/device.c:1010 [inline]
 remove_compat_devs drivers/infiniband/core/device.c:1022 [inline]
 disable_device+0x1c0/0x260 drivers/infiniband/core/device.c:1304
 __ib_unregister_device+0x1fb/0x2d0 drivers/infiniband/core/device.c:1527
 ib_unregister_work+0x19/0x30 drivers/infiniband/core/device.c:1639
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0x513/0xa10 kernel/workqueue.c:3359
 worker_thread+0x58a/0x780 kernel/workqueue.c:3440
 kthread+0x22a/0x280 kernel/kthread.c:436
 ret_from_fork+0x150/0x360 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 4579 Comm: kworker/u8:27 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: ib-unreg-wq ib_unregister_work
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